Belt-drive.



P. T. LINDHARD.

BELT DRIVE.

APPLIOATIOH FILED AUG. 27, 1910,.

Patented June 20, 1911.

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P. T. LINDHARD.

BELT DRIVE.

APPLIOATIOH run we. 27; 1910.

996,022, Patented June 20, 1911.

3 SHEETS-SHEET 2.

THE Nonms Fsnrns co., wnsnmumn, n. c.

P. T. LINDHARD.

BELT DRIVE.

APPLICATION FILED we. 27, 1910.

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Patented June 20, 1911.

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0.. Iluwumrou a UNITED STATES POVL T. LINDHARD, OF NEW YORK, N. Y.,

ASSIGNOR. TO 13. L. SMIDTH 8c (30., OF NEW YORK, N. Y., A CORPORATION OFNEW JERSEY.

BELT-DRIVE.

Specification of Letters Patent.

Patented June 20, 1911.

Application filed August 27, 1910. Serial No. 579,361.

To all whom it may concern:

Be it known that I, PovL T. LINDHARD, a subject of the King of Denmark,residing at Flatbush, in the borough of Brooklyn of the city of NewYork, in the State of New York, have invented certain new and usefulImprovements in Belt-Drives, of which the following is a specification,reference being had to the accompanying drawings, forming a part hereof.

The efliciency of any belt drive is dependent upon the friction betweenthe belt and the belt pulley, either driver or driven, or both, theratio between the tension of the tight or driving side of the belt andthe slack side of the belt, which determines the efliciency of thedriving, being increased with the friction. It is possible to increasethe friction between the belt and the pulley either by increasing thearc of contact between the belt and the pulley. by the use of idlers onthe slack side of the belt, or by increasing the co-eflicient offriction between the belt and the pulley.

Various devices are resorted to for the purpose of increasing theco-eflicient of friction between the ordinary leather, rubber or wovenbelts and pulleys with which they cooperate and the results secured aremore or less satisfactory. Greater difficulties have heretoforepresented themselves, however, in the attempts to increase theoo-efiicient of friction between metallic belts or belts which embodymetal in their structure, and their cooperating pulleys, and it has beenproposed, for example, to provide such belts with a surface covering ofcork, leather or other material, but thus far such means have not provedsatisfactory because of the great expense of manufacture and limiteddurability of the belts.

It is therefore the object of this invention to provide improved meansfor increasing the co-efiicient of friction between a metallic belt,that is, a belt which embodies in its structure more or less metal whichis capable of being magnetized, and its cooperating pulley and inaccordance with the invention the pulley or the rim thereof ismagnetized so that the belt may be made thereby to hug closely theperiphery of the pulley and the total friction between the belt and thepulley be thereby increased, with the ultimate result of increasinglargely the efficiency of the drive. Means are also provided forneutralizing the magnetism of the pulley or demagnetizing the pulley atthe point where the belt should leave the periphery of the pulley sothat there shall be no waste of power nor unnecessary strain upon thebelt in causing it to separate from the periphery of the pulley.

The invention will be more fully explained hereinafter with reference tothe accompanying drawings in which it is illustrated, and in whichFigure 1 is a view in elevation showing a driving pulley mounted inbearings and provided with means for magnetizing its rim and with meansfor demagnetizing its rim at a determined point. Fig. 2 is a view inside elevation of the parts shown in Fig. 1, a portion of the belt beingalso represented. Fig. 3 is a view showing two driving pulleys and theirbelt with an idler applied to the slack side of the belt anddemagnetizing devices supported in proper position with respect to thepulleys. Fig. 4 is a detail view in diametrical section and on a largerscale than Fig. 1, showing the construction of the pulley with the beltin position thereon. Fig. 5 is a detail edge or face view of a portionof the pulley shown in Figs. 1 and 4. Fig. 6 is a view similai to Fig. 5but showing a modification in the form of the face of the pulley. Figs.7, 8 and 9 are detail views in circumferential section, in radialsection and in face view respectively, showing still anothermodification in the form of the pulley. Figs. 10 and 11 are detail viewsillustrating still other modifications. Fig. 12 is a detail view showingthe pulley provided with two parallel exciting coils and with acorresponding demagnetizing device. Fig. 13 is a view similar to Fig. 12but showing the pulley provided with three exciting coils. Figs. 14 and15 are detail views illustrating a modification in the arrangement ofthe demagnetizing device.

The belt a, as will be well understood, is

formed of or has incorporated in its structure a magnetizable metal andfor convenience is referred to herein as a metallic belt. The pulley orpulleys Z), or b, or each of them, with which the metallic belt acooperates, may be constructed in any usual or suitable manner, eitherwholly or in part of metal, its rim 0, at least, being formed in wholeor in part of a metal which is capable of being magnetized so as to drawto it the metallic belt which cooperates with it. ()bviously the rim ofthe pulley may be magnetized in any suitable manner. As shown in Figs.1, 4 and 5, the rim of the pulley is divided circumferentially, as by acircumferential slot (1, forming thereby two magnetic poles of oppositepolarity. The rim is also preferably chambered circumferentially, as atf, to receive an exciting coil g of wire, the ends of which may beconnected to slip rings h mounted on the supporting shaft 2', so that acurrent of electricity may be there by passed through the exciting coilfrom any suitable source. Flanges K: may be provided, if desired, toprevent the belt from working laterally on the face of the pulley.

As indicated hereinbefore, means are provided for neutralizing themagnetism of the pulley or for demagnetizing the pulley at the pointwhere the belt a leaves the periphery thereof, in order that the beltmay not be strained unnecessarily and that there may be no loss of powerin the separation of the belt from the pulley. The neutralizing ordemagnetizing device may be constructed and arranged in any suitablemanner. As shown in Figs. 1 and 2 it may consist of a horseshoe magnet Zwith its poles so placed in relation to the rim of the pulley as todivert the lines of magnetic force at the point where the belt leavesthe face of the pulley. This magnet may be supported by arms at from theshaft 5 of the pulley and held in the desired position by any suitablemeans. It is shown as wound with a coil of wire it through which anexciting current may be passed from any suitable source.

The demagnetizing device should be positioned properly with respect tothe point where the belt leaves the pulley. Thus, in the arrangementshown in Fig. 3 in which a large pulley b and a small pulley Z) areconnected by a belt a with a weighted idler 0 on the slack side of thebelt, the demagnetizing device Z should be placed with respect to thepulley b as shown in the drawings when the pulley b is driven from thepulley b. The small pulley I) being then the driver, its demagnetizmgdevice Z should be placed as shown in the drawings and may beconveniently supported by the arm which carries the idler 0. On theother hand if the large pulley is the driver and the small pulley isdriven the positions of the demagnetizing devices obviously should bechanged. Such an arrangement as that shown in this Fig. 3 of thedrawings possesses a very high efliciency, for not only is the arc ofcontact between the belt and each ulley the maximum possible, but theco-e cient of friction between the belt and the pulley is also veryhigh.

In the modification of the pulley shown in Fig. 6 the slot cl betweenthe pole pieces e and c is serpentine instead of straight, therebyincreasing the number of magnetic lines of force which pass through thebelt and therefore increasing the eo-etlicient of friction,

In the modification shown in Figs. 7, 8 and 9, tapered pins (Z aresecured in flanges k and la in alternation, pointing inward andflattened on the outer surface to give a smooth bearing to the belt.These pins or pieces may be made of a difierent quality of iron or steelfrom that employed in the formation of the wheel rim and therefore bebetter adapted to serve as magnetic poles and secure a higherefficiency.

In the modification shown in Fig. 10 the face of the pulley is formedwith longitudinal grooves 0, while in the modification shown in Fig. 11the face of the pulley is formed with transverse grooves 0 these groovesserving to increase the frictional contact between the belt and the faceof the pulley.

As shown in Figs. 12 and 13 the rim 0 may be provided with two or morechambers f and exciting coils g therein as the width of the pulley facemay require and the demagnetizing device Z will have its north and southpoles Z and Z suitably arranged to cooperate with the pulley rim asrepresented.

In Figs. 14 and 15 a comparatively narrow pulley is shown as providedwith a plurality of narrow chambers f and corresponding coils g and thedemagnetizing device Z has its poles suitably arranged to cooperate withthe pulley rim.

Various other embodiments of the invention will readily suggestthemselves in view of the foregoing and it is to be understood,therefore, that the invention is not restricted to any particular formbut may be embodied in a great variety of structures suited to theparticular requirements of different uses.

I claim as my invention:

1. A belt pulley having a rim of magnetizable metal, means to magnetizethe rim and means to demagnetize the rim.

2. The combination of a magnetic belt, a belt pulley having a rim ofmagnetizable metal, means to magnetize the rim and means to demagnetizethe rim.

3. The combination of a magnetic belt, belt pulleys, means to magnetizeone of said pulleys, a belt tightener applied to the slack side of thebelt, and means to demagnetize the magnetic pulley.

4. A belt pulley having a. rim divided cir- This specification signedand. witnessed cumferentially in a zigzag line to form magthis 30th dayof July, A. D., 1910.

netie poles.

5. A belt pulley having a rim divided cir- POVL LINDHARD' cumferentiallyin a zigzag line to form mag- Signed in the presence ofnetic poles andexciting coils applied to the AMBROSE L. OSI-IEA, rim. E. A. GERKEN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

